Benefit Plans and Other Postretirement Benefits, Changes in Level 3 Pension Plan Assets (Details) (Pension Plans, USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
Changes in Level 3 Plan Assets [Roll Forward]
Fair value of plan assets at Dec. 31	$ 1,067,057		$ 1,055,308	$ 969,207
Level 3
Changes in Level 3 Plan Assets [Roll Forward]
Fair value of plan assets at Jan. 1	82,991		94,157	102,915
Net realized gains (losses)	6,204		6,937	2,072
Net unrealized gains (losses)	(258)		(7,380)	7,407
Purchases, issuances and settlements, net	1,967		(10,723)	(18,237)
Transfers in (out) of Level 3	(26,326)	[1]	0	0
Fair value of plan assets at Dec. 31	64,578		82,991	94,157
Asset-backed securities
Changes in Level 3 Plan Assets [Roll Forward]
Fair value of plan assets at Dec. 31	2,356		4,604
Asset-backed securities | Level 3
Changes in Level 3 Plan Assets [Roll Forward]
Fair value of plan assets at Jan. 1	4,604		9,824	8,399
Net realized gains (losses)	0		1,175	713
Net unrealized gains (losses)	0		(1,597)	(744)
Purchases, issuances and settlements, net	0		(4,798)	1,456
Transfers in (out) of Level 3	(4,604)	[1]	0	0
Fair value of plan assets at Dec. 31	0		4,604	9,824
Mortgage-backed securities
Changes in Level 3 Plan Assets [Roll Forward]
Fair value of plan assets at Dec. 31	5,267		12,058	23,614
Mortgage-backed securities | Level 3
Changes in Level 3 Plan Assets [Roll Forward]
Fair value of plan assets at Jan. 1	12,058		23,614	36,134
Net realized gains (losses)	0		550	320
Net unrealized gains (losses)	0		(625)	(1,774)
Purchases, issuances and settlements, net	0		(11,481)	(11,066)
Transfers in (out) of Level 3	(12,058)	[1]	0	0
Fair value of plan assets at Dec. 31	0		12,058	23,614
Private equity investments
Changes in Level 3 Plan Assets [Roll Forward]
Fair value of plan assets at Dec. 31	49,022		47,056
Private equity investments | Level 3
Changes in Level 3 Plan Assets [Roll Forward]
Fair value of plan assets at Jan. 1	47,056		49,489	36,420
Net realized gains (losses)	7,074		5,206	1,229
Net unrealized gains (losses)	(4,027)		(7,001)	3,925
Purchases, issuances and settlements, net	(1,081)		(638)	7,915
Transfers in (out) of Level 3	0	[1]	0	0
Fair value of plan assets at Dec. 31	49,022		47,056	49,489
Real estate
Changes in Level 3 Plan Assets [Roll Forward]
Fair value of plan assets at Dec. 31	15,556		19,273	11,230
Real estate | Level 3
Changes in Level 3 Plan Assets [Roll Forward]
Fair value of plan assets at Jan. 1	19,273		11,230	21,962
Net realized gains (losses)	(870)		6	(190)
Net unrealized gains (losses)	3,769		1,843	6,000
Purchases, issuances and settlements, net	3,048		6,194	(16,542)
Transfers in (out) of Level 3	(9,664)	[1]	0	0
Fair value of plan assets at Dec. 31	$ 15,556		$ 19,273	$ 11,230

[1] Transfers out of Level 3 into Level 2 were principally due to diminished use of unobservable inputs that were previously significant to these fair value measurements and were subsequently sold during 2013.